The field of the invention is chiropractic instruments and the invention relates more particularly to instruments of the type which are used to adjust a patient's spine. Numerous instruments have been used for the purpose of providing a controlled striking force against a portion of a patient's body. Instruments used for testing reflex action in order to determine the reaction sensitivity of a patient's nervous system are disclosed in U.S. Pat. Nos.: 2,800,895, 3,185,146, and 3,626,927. Other tools for providing a striking force with increased impact are utilized in metal working and such devices are shown in U.S. Pat. Nos. 3,130,762, 3,172,438 and 4,039,012.
There is a need, however, for an instrument which provides improved control by a chiropractor or other practitioner to provide the desired amount of impact to a patient. Whereas devices such as that shown in the Torricelli Hand Reflex Gun, U.S. Pat. No. 2,800,895, utilize a spring with markings which permit the user to compress the spring in a predetermined amount, it is believed that this does not provide sufficient feel for the doctor to provide an appropriate amount of impact.
There is thus a need for an instrument which provides the practitioner with an improved amount of sensitivity to enable him to provide a predetermined proper amount of impact against a patient.